Intermittent NullReferenceException on client side calling gRPC

[wangjia184]

<PackageReference Include="protobuf-net" Version="3.2.12" />
<PackageReference Include="protobuf-net.Grpc" Version="1.1.1" />

I am receiving intermittent error when calling gRPC API.

NullReferenceException

RpcException Status(StatusCode="Internal", Detail="Error starting gRPC call. NullReferenceException: Object reference not set to an instance of an object.", DebugException="System.NullReferenceException: Object reference not set to an instance of an object.
  at Grpc.Net.Client.Internal.GrpcCallSerializationContext.GetMemory(Int32 sizeHint)
  at ProtoBuf.ProtoWriter.BufferWriterProtoWriter.GetBuffer(State& state) in /_/src/protobuf-net.Core/ProtoWriter.BufferWriter.cs:line 139
  at ProtoBuf.ProtoWriter.BufferWriterProtoWriter.ImplWriteVarint32(State& state, UInt32 value) in /_/src/protobuf-net.Core/ProtoWriter.BufferWriter.cs:line 189
  at ProtoBuf.Serializers.ListSerializer`2.Write(State& state, Int32 fieldNumber, SerializerFeatures category, WireType wireType, TList values, ISerializer`1 serializer, SerializerFeatures features) in /_/src/protobuf-net.Core/Serializers/RepeatedSerializer.cs:line 392
  at ProtoBuf.Serializers.RepeatedSerializer`2.WriteRepeated(State& state, Int32 fieldNumber, SerializerFeatures features, TCollection values, ISerializer`1 serializer) in /_/src/protobuf-net.Core/Serializers/RepeatedSerializer.cs:line 135
  at proto_35(State& , UpdateWalletsRequest )
  at ProtoBuf.ProtoWriter.State.SerializeRoot[T](T value, ISerializer`1 serializer)
  at ProtoBuf.MeasureState`1.SerializeCore(State state)
  at ProtoBuf.MeasureState`1.Serialize(IBufferWriter`1 writer)
  at ProtoBuf.Meta.TypeModel.ProtoBuf.IMeasuredProtoOutput<System.Buffers.IBufferWriter<System.Byte>>.Serialize[T](MeasureState`1 measured, IBufferWriter`1 destination)
  at ProtoBuf.Grpc.Configuration.ProtoBufMarshallerFactory.ContextualSerialize[T](T value, SerializationContext context)
  at Grpc.Net.Client.StreamExtensions.WriteMessageAsync[TMessage](Stream stream, GrpcCall call, TMessage message, Action`2 serializer, CallOptions callOptions)
  at Grpc.Net.Client.Internal.PushUnaryContent`2.WriteMessageCore(ValueTask writeMessageTask)
  at System.Net.Http.Http2Connection.Http2Stream.SendRequestBodyAsync(CancellationToken cancellationToken)
  at System.Net.Http.Http2Connection.SendAsync(HttpRequestMessage request, Boolean async, CancellationToken cancellationToken)
  at System.Net.Http.HttpConnectionPool.SendWithVersionDetectionAndRetryAsync(HttpRequestMessage request, Boolean async, Boolean doRequestAuth, CancellationToken cancellationToken)
  at System.Net.Http.RedirectHandler.SendAsync(HttpRequestMessage request, Boolean async, CancellationToken cancellationToken)
  at Grpc.Net.Client.Balancer.Internal.BalancerHttpHandler.SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
  at Grpc.Net.Client.Internal.GrpcCall`2.RunCall(HttpRequestMessage request, Nullable`1 timeout)")